The present invention relates to a lock for sliding doors or panels. Particularly, the present invention relates to a sliding door lock having a lock cylinder that is mountable in a first sliding door and a lock core that is slidably extendable from its normal position within the lock cylinder to block movement of an adjacent second sliding door in relation to the first sliding door.
Push locks for sliding doors are known. Sliding doors are commonly locked by operating a push-button to project a bolt assembly from the face of one door into a keeper on the overlapping door. A representative push-button sliding door lock is disclosed in Blekking et al., U.S. Pat. No. 3,798,935. Although such a sliding door lock functions in the intended manner, it will be appreciated that it is necessary to: install a push button cylinder assembly on an outer sliding door or door frame, install a separate keeper mechanism in the adjacent inner sliding door, provide a bolt assembly for lockably engaging the keeper, provide a key-operated lock core and means for interconnecting the lock core and separate bolt assembly.
These added features required by the design of the '935 patent undesirably increase the cost and the complexity of the sliding door lock. It will be appreciated that the lock cylinder disclosed in the '935 patent is generally mounted in the base of the cabinet instead of in one of the sliding doors themselves since the sliding doors are typically made of glass and the known lock is not adapted for mounting in a glass door or panel. The base must be made undesirably heavy to accommodate and support such a lock cylinder. Typically, the lock is permanently installed in the frame or other base. One disadvantage of this arrangement is that the frame must be disassembled completely to remove the lock for maintenance reasons. It may also be necessary to mount the keeper assembly in a glass door which disfigures the inner sliding door and increases installation time. In addition, two separate keys must be provided to install and operate the lock core. The control key is used to fix the interchangeable lock core in the lock cylinder defined by a push-button plunger while the operating key is used to rotate the bolt assembly between its locking and release positions. The keys are removable only when the lock core is in its locked position.
Sliding panel locks are also known. One example is the 2P Series sliding panel lock sold by Best Lock Corporation of Indianapolis, Ind. Typically, a strike strap and a cylinder cooperate to form a blocking arrangement. The strike strap includes a hooked tongue at one end and securement means at the other end. When the panels are closed, the hooked tongue of the strike strap extends beyond the edge of the outer panel. To lock the inner and outer panels together, a pin in the lock core engages the securement means of the strike strap. Locking engagement of the lock core and the strike strap is accomplished by key operation of the lock core. A control key is used to fix the interchangeable lock core in the lock housing while an operating key is used to interengage the lock core pin and the securement means of the strike strap. This unit is entirely separate from the sliding panels. One disadvantage is that the unit comes apart into two pieces when the key is operated to withdraw the pin from the strike since the unit is not permanently attached to the sliding panels. The keys are removable only when the lock core is in its locked position.
A lock for sliding doors or panels that is easily mounted on one of the doors itself instead of on the door frame and that does not require that additional keepers or the like be mounted on the other door, is designed to receive a key-operated interchangeable lock core that is itself movable to block relative movement of a pair of sliding doors without additional keeper-engaging bolt assembly, and is adaptable to permit removal of the lock-operating key when the lock core is in either of its locked or unlocked positions would avoid the shortcomings of conventional lock systems.
According to the present invention, a lock is provided for use in preventing relative movement of first and second sliding panels arranged in side-by-side passing relation. The lock includes a lock cylinder that is mounted in the first sliding panel and has an inner wall defining a core-receiving chamber. The lock further includes a lock core that has a slot for receiving a key and is slidably mounted in the core-receiving chamber for movement between a projected and retracted position. In its projected position, the lock core substantially blocks movement of the second sliding panel in relation to the first sliding panel. In its retracted position, the lock core permits unhindered movement of the second sliding panel in relation to the first sliding panel.
The second sliding panel is movable along a path that is spaced-apart from the path of the first sliding panel in the customary way. However, in contrast to known locking systems, the lock core of the present invention is projectable from the lock cylinder mounted in the first sliding panel to intersect the path of the second sliding panel. Thus, the lock core itself may be positioned to intercept and engage an edge of the second sliding panel to block relative movement of the first and second sliding panels thereby locking the closed panels.
One feature of the present invention is the provision of a lock core slidably mounted in the core-receiving chamber for movement between a projected position substantially blocking movement of the second sliding panel in relation to a first sliding panel and a retracted position permitting unhindered movement of the second sliding panel in relation to the first sliding panel. This feature advantageously simplifies the construction and installation of the novel lock in comparison to known locks.
In construction, the actual panel-locking mechanism used in the present invention is defined by the lock core itself. A user can project the lock core initially positioned in an outer sliding panel into the path of an adjacent inner sliding panel to intercept and block the inner panel so that both panels are unable to slide open when the lock core is retained in its projected inner panel-locking position. The lock core advantageously provides a solid panel-blocking member and is easily adapted for use in a sliding door locking system since it is unnecessary to provide and assemble conventional panel-locking bolt and keeper mechanisms for interconnecting the panels and the lock core. Thus, the novel construction reduces the complexity of the lock thereby providing a more economical and efficient lock.
Installation is accomplished easily by mounting the lock cylinder in a hole cut in the outer sliding panel and then inserting the lock core into the mounted lock cylinder. It is unnecessary to provide additional brackets, straps, or the like as is customary in known sliding door locking systems since the lock core is slidable within the lock cylinder to block relative movement of two sliding panels. In addition, the lock cylinder can be mounted directly in a glass panel or the like. It is unnecessary to provide a heavy base or frame for supporting any part of the novel lock. One advantage of this feature is that installation of the novel lock in any existing panels is accomplished easily since it is only necessary to cut a cylinder-receiving hole in one of the existing panels. Thus, the versatile lock of the present invention can be mounted easily to lock display cabinets, window displays, or other storage areas that are closed by sliding panels of glass, plastic, wood or the like.
Another feature of the present invention is that the lock core is retainable in its projected panel-locking position by engagement of the lock core control lugs and the lock cylinder. This feature advantageously simplifies the operation of the lock. In operation, release of the lock core for axial movement between its projected panel-locking position and its retracted panel-unlocking position advantageously is accomplished solely by means of a single "control" key thereby avoiding the need for a separate "operating" key. The sliding panels are unlocked by rotating the control key to disengage the control lug in the lock cylinder and then pulling the lock core forward from its projected panel-locking position to its retracted panel-unlocking position.
Yet another feature of the present invention is that the sliding door lock is adaptable to permit removal of the lock-operating control key whether or not the lock core control lugs engage the lock cylinder lug to retain the lock core in a selected position within the lock cylinder. One advantage of the present invention is that the lock core is easily adapted to provide a "convenience version" as disclosed in a first embodiment or a "higher security version" as disclosed in a second embodiment without interfering with the novel panel-blocking function of the lock core itself. In the first embodiment, the lock core includes two separate control lugs to permit the key to be removable in the locked or unlocked position, whereas in the second embodiment the key is removable only in the locked position. The novel key-removal feature of the first embodiment is advantageous in that it is desirable in many instances to remove the key from the lock core. For example, in many retailing applications it is necessary to leave a display cabinet having sliding doors unlocked during business hours. In these situations, the security manager does not wish to permit a customer to steal the unattended key left in the key slot by simply returning the lock mechanism to its locked position and then removing the key.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.